Douglas C. Knipple

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Drosophila melanogaster cuticular pheromones consist of unsaturated hydrocarbons with at least one double bond in position 7: 7 tricosene (T) in males and 7,11 heptacosadiene (HD) in females. However, in many African populations like the Tai strain, females possess low levels of 7,11 HD and high levels of its positional isomer 5,9 HD. We have previously(More)
The kdr insecticide resistance trait of the house fly (Musca domestica .L.), which confers reduced neuronal sensitivity to DDT and pyrethroid insecticides, was previously shown to exhibit tight genetic linkage to restriction fragment length polymorphism markers lying within a voltage-sensitive sodium channel gene that is homologous to the para gene of(More)
Lepidopteran insects use sex pheromones derived from fatty acids in their species-specific mate recognition system. Desaturases play a particularly prominent role in the generation of structural diversity in lepidopteran pheromone biosynthesis as a result of the diverse enzymatic properties they have evolved. These enzymes are homologous to the integral(More)
The term "knockdown resistance" is used to describe cases of resistance to diphenylethane (e.g. DDT) and pyrethroid insecticides in insects and other arthropods that result from reduced sensitivity of the nervous system. Knockdown resistance, first identified and characterized in the house fly (Musca domestica) in the 1950's, remains a threat to the(More)
The super-kdr insecticide resistance trait of the house fly confers resistance to pyrethroids and DDT by reducing the sensitivity of the fly nervous system. The super-kdr genetic locus is tightly linked to the Vssc1 gene, which encodes a voltage-sensitive sodium channel alpha subunit that is the principal site of pyrethroid action. DNA sequence analysis of(More)
In this investigation, we examined the effects of different unsaturated fatty acid compositions of Saccharomyces cerevisiae on the growth-inhibiting effects of ethanol. The unsaturated fatty acid (UFA) composition of S. cerevisiae is relatively simple, consisting almost exclusively of the mono-UFAs palmitoleic acid (Delta(9)Z-C(16:1)) and oleic acid(More)
The demonstration that a specific messenger RNA can be functionally inactivated in vivo by hybridization to complementary polynucleotide sequences suggests a direct approach to the study of gene function in cells of higher organisms. The experiments described here were designed to inhibit, by complementary RNA sequences, a specific gene function affecting(More)
The Krüppel (Kr) locus is a member of the 'gap' class of segmentation genes of Drosophila melanogaster. Mutations at the Kr locus cause the deletion of contiguous segments from the embryonic body pattern. We have elucidated the spatial and temporal characteristics of Kr gene expression during early embryo development, the localization of cytoplasmic Kr+(More)
Sequence analysis of cDNA clones amplified by PCR from house fly (Musca domestica L.) Vssc1 voltage-sensitive sodium channel α subunit transcript templates identified 11 putative alternatively spliced exons. Nine of these corresponded to the 7 optional exons (designated a, b, e, f, h, i, and j) and 2 mutually exclusive exons (designated c/d) identified(More)
In this report, we describe the structural and functional analyses of four acyl-CoA desaturase-encoding cDNAs that we isolated from RNA expressed in the pheromone gland of the corn earworm, Helicoverpa zea. We deduced the homology relationships of the encoded proteins, designated HzPGDs1, HzPGDs2, HzPGDs3 and HzFBDs, to each other and to previously(More)